Transcriptomic insight into the immune defenses in the ghost moth, Hepialus xiaojinensis, during an Ophiocordyceps sinensis fungal infection
Transcriptomic insight into the immune defenses in the ghost moth, Hepialus xiaojinensis, during an Ophiocordyceps sinensis fungal infection
复制标题
转录组学研究幽灵蛾（Hepialus xiaojinensis）在冬虫夏草真菌感染期间的免疫防御
DOI：
10.1016/j.ibmb.2015.06.014
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发表时间：
2015-09-01
影响因子：
3.8
通讯作者：
Zou, Zhen
中科院分区：
文献类型：
--
作者：
Meng, Qian;Yu, Hai-Ying;Zou, Zhen
小金蝠蛾（Hepialus xiaojinensis）是鳞翅目昆虫中重要的经济物种。真菌冬虫夏草可以感染其幼虫，并在 5-12 个月后导致木乃伊化，为研究昆虫宿主和病原真菌之间的相互作用提供了一个有价值的系统。然而，关于这种昆虫的序列信息很少。对脂肪体转录组进行时程分析，以探讨宿主对中华圆线虫感染的免疫反应。通过组装两种高通量方法的读数，总共获得了 50,164 个 unigene：454 焦磷酸测序和 Illumina Hiseq2000。层次聚类和功能检查揭示了四个主要基因簇。簇 1-3 包括 72 小时内由真菌感染显着诱导的转录本。转录本数量较少的簇 4 在感染早期受到抑制，但在 1 年前的某个时候恢复到正常表达水平。基于与已知参与免疫防御的直向同源物的序列相似性，鉴定了 258 个候选免疫相关转录本，并假设了它们的功能。这些基因比其他鳞翅目昆虫的基因更为原始。此外，夹域丝氨酸蛋白酶和C型凝集素的谱系特异性家族扩张是明显的，并且可能是由选择压力引起的。免疫相关基因的整体表达谱表明，小金汉蛇能够对中华汉蛇的攻击做出快速反应；然而，幼虫在长期感染后对真菌产生了耐受性，这可能是由于免疫抑制。具体来说，慢性感染后无法检测到抗菌肽 mRNA，因为 Toll 通路的关键成分（MyD88、Pelle 和 Cactus）下调。总而言之，这项研究提供了对小金 H. xiaojinensis 防御系统的见解，并为理解宿主与昆虫病原体之间相互作用的分子方面奠定了基础。 (C) 2015 Elsevier Ltd. 保留所有权利。
Hepialus xiaojinensis is an economically important species of Lepidopteran insect. The fungus Ophiocordyceps sinensis can infect its larvae, which leads to mummification after 5-12 months, providing a valuable system with which to study interactions between the insect hosts and pathogenic fungi. However, little sequence information is available for this insect. A time-course analysis of the fat body transcriptome was performed to explore the host immune response to O. sinensis infection. In total, 50,164 unigenes were obtained by assembling the reads from two high-throughput approaches: 454 pyrosequencing and Illumina Hiseq2000. Hierarchical clustering and functional examination revealed four major gene clusters. Clusters 1-3 included transcripts markedly induced by the fungal infection within 72 h. Cluster 4, with a lower number of transcripts, was suppressed during the early phase of infection but returned to normal expression levels sometime before 1 year. Based on sequence similarity to orthologs known to participate in immune defenses, 258 candidate immunity-related transcripts were identified, and their functions were hypothesized. The genes were more primitive than those in other Lepidopteran insects. In addition, lineage-specific family expansion of the clip-domain serine proteases and C-type lectins were apparent and likely caused by selection pressures. Global expression profiles of immunity-related genes indicated that H. xiaojinensis was capable of a rapid response to an O. sinensis challenge; however, the larvae developed tolerance to the fungus after prolonged infection, probably due to immune suppression. Specifically, antimicrobial peptide mRNAs could not be detected after chronic infection, because key components of the Toll pathway (MyD88, Pelle and Cactus) were downregulated. Taken together, this study provides insights into the defense system of H. xiaojinensis, and a basis for understanding the molecular aspects of the interaction between the host and the entomopathogen. (C) 2015 Elsevier Ltd. All rights reserved.